VUB

PHYSICAL CHEMISTRY & POLYMER SCIENCE (FYSC)

• Synthesis, processing, and characterization of polymers with a focus on structure-processing-property relationships
• Characterization of polymer-based materials by advanced thermal analysis techniques
• Modelling of polymer processing including heat transfer and reaction or crystallization kinetics
• Thermosetting polymer systems
• Polymer nanofibers, nanocomposites, and interphases
• Polymer coatings and thin layers
• Polymer-based organic photovoltaics
• Self-healing polymers and Stimuli-responsive polymers

POLYMER CHARACTERIZATION

FYSC focuses on studying structure-property-relationships in polymer-based materials and developing the advanced thermal analysis techniques and methods needed for this purpose. The thermal analysis equipment available comprises conventional thermal analysis techniques like:

• differential scanning calorimetry (DSC),
• thermogravimetric analysis (TGA),
• dynamic mechanical analysis (DMA),
• thermomechanical analysis (TMA).

Extended with advanced thermal analysis techniques for:

• measuring transitions more sensitively: modulated temperature differential scanning calorimetry (MTDSC), micro- and nanocalorimetry,
• faster transformations, suitable for thin films and ultra-small samples: rapid-heat-cool DSC (RHC) and ultra fast scanning chip-based calorimetry,
• spatially localized thermal analysis at the micro- and nanometer level using scanning probe microscopy based methods (µTA and nanoTA),
• and novel in-house developed hyphenated thermal techniques permitting combinations of measurements on a single sample (RheoDSC)

This is further supported by

• dynamic rheometry in an extended temperature range,
• gel permeation chromatography, specifically equipped for copolymer analysis,
• spectroscopic techniques: FTIR, UVVis, NMR, Raman,
• microscopy and surface analysis techniques: AFM, SEM and SEM-EDX, XPS, Auger EM, Raman microscopy.

NANOSTRUCTURED POLYMERS

Research on the development and characterization of novel, functional nano-structured polymer-based materials focuses on nanocomposites and nano-structured active layers for organic photovoltaics. For nanocomposites this involves the design and synthesis of (co)polymers for nanofiller dispersion, the development of methods to study the influence of polymer-filler combinations and processing conditions on the nanofiller dispersion, and the characterization of the materials at all stages. FYSC is also active in the synthesis and fabrication of functional inorganic and organic nanoparticles for inclusion in polymer nanocomposites.

For organic photovoltaics, we currently focus on the study of state diagrams and morphology formation processes in the active layer of polymer-fullerene bulk heterojunction solar cells. As the application thickness of these layers is about 100 nm, ultrafast scanning chip calorimetry is used because it enables us to follow the formation of (metastable) structures in 100 nm thin samples. (with Universiteit Hasselt http://www.uhasselt.be/IMO).

SELF-HEALING POLYMERS

Research in self-healing polymers is centred on three types of self-healing principles: systems with encapsulated healing agents, reversible covalent or physically bounds networks, and nanovascular systems with reacting healing agents.

The systems with encapsulated healing agents, either reactive ones or solvents, are studied with industrial and academic partners (SIM-SHE programme http://www.sim-flanders.be/research-program/she). In addition, we are developing nanovascular systems with reactive self-healing agents, making use of sacrificial templates made by electrospinning (with Department of Textiles of UGent (http://www.ugent.be/ea/textiles).

In-house, we are developing a series of thermoreversible covalent networks. These thermoreversible networks with tuneable properties display self-healing upon heating to 70-90°C. Recently these materials were successfully used for creating the first self-healing actuators for robotic applications. (with Robotics and MultiBody Mechanics Research Group, http://mech.vub.ac.be/multibody_mechanics.htm, VUB).
Together with the PCR group of UGent (www.pcr.ugent.be), photoreversible covalent networks are being developed.

COMPOSITES & ENGINEERING

FYSC has more than 30 years of experience in studying and modelling polymerization or cure kinetics and crystallization kinetics, as well as their combination with heat transfer modelling for simulating polymer processing. Recent work in this field includes:

• the modelling of the cure kinetics and chemorheology of thermosetting polymers for composite or bulk applications,
• the modelling of the cooling and crystallization of thermoformable masks for medical application,
• the modelling of photo-induced polymerization reactions for laser-induced generation of 3D structures,
• the modelling of the crystallization or cure of injection-moulded field joint coatings for deep-sea pipelines.

This modelling work is done with COMSOL finite element modelling software http://www.comsol.com/ and in-house developed software for developing reaction and crystallization kinetics models.